1. Field of the Disclosure
This disclosure relates in general to organic electronic devices and particularly to devices used for lighting.
2. Description of the Related Art
In organic electronic devices, such as organic light emitting diodes (“OLED”), that make up OLED displays or OLED lighting devices, the organic active layer is sandwiched between two electrical contact layers. In an OLED, at least one of the electrical contact layers is light-transmitting, and the organic active layer emits light through the light-transmitting electrical contact layer upon application of a voltage across the electrical contact layers.
It is well known to use organic electroluminescent compounds as the active component in light-emitting diodes. Simple organic molecules, conjugated polymers, and organometallic complexes have been used. Devices frequently include one or more charge transport layers, which are positioned between a photoactive (e.g., light-emitting) layer and an electrical contact layer. A device can contain two or more contact layers. A hole transport layer can be positioned between the photoactive layer and the hole-injecting contact layer. The hole-injecting contact layer may also be called the anode. An electron transport layer can be positioned between the photoactive layer and the electron-injecting contact layer. The electron-injecting contact layer may also be called the cathode. Charge transport materials can also be used as hosts in combination with the photoactive materials.
There is a continuing need for devices with improved properties.